Tap head for keg fittings

ABSTRACT

A tap head for keg fittings comprises a sliding guide means containing an annular seal and a guideway for pushing the tap head onto the protruding rim of a plate of the keg fittings, wherein at least the sliding guide means of the tap head consists of spring elastic material and a projecting guide piece of the guideway engages under the rim of the plate. The modulus of elasticity of the material forming the sliding guide means and the geometry and the dimensions of the guide piece are determined such that the guide piece undergoes deformation at a predetermined gas pressure in the housing of the tap head and a gap for the release of excess gas pressure is formed between the plate and the annular seal.

The invention relates to a tap head for keg fittings according to thepreamble to patent claim 1.

A tap head of this type is known from DE-PS 39 02 527.

Provision of a pressure relief valve which opens when there is apredetermined excess gas pressure in the keg and tap head to preventexplosion-like bursting of the barrel-like keg and the tap head in theevent of excessive gas pressure is often desired and sometimes alsoprescribed by the authorities for such tap heads. Known pressure reliefvalves (DE-OS 29 39 536) for this purpose are designed as separatecomponents which have to be manufactured separately and insertedsubsequently in a sealed state into a wall of the tap head housing.

The object of the invention is to so design a generic tap head thatrelease of an inadmissibly high excess gas pressure in the keg and taphead is possible without using a separate pressure relief valve.

The object is accomplished with a generic tap head by the features inthe characterizing clause of patent claim 1.

It is known from DE-OS 37 01 432 to allow pressure gas to escape througha gap between a plate on the barrel and an annular seal on the tap headwith the shut-off valves of a tap head in the closed state. However, theknown configuration cannot be used as a pressure relief valve. In a taphead of a different type, DE-GM 91 10 371 shows a sliding guide meansfor barrel fittings which is placed as a separate component on the taphead housing.

Preferred embodiments of the invention are the subject matter ofsubclaims 2 and 3.

The following description serves to explain the invention in greaterdetail in conjunction with the attached drawings, in which

FIG. 1 is a part-sectional side view of a tap head for keg fittings witha sliding guide means in the normal operating state;

FIG. 2 shows the tap head of FIG. 1 in a position in which it is liftedoff the keg fittings owing to excess gas pressure;

FIG. 3 is a plan view of the tap head of FIG. 2;

FIG. 4 is a part-sectional front view of the tap head with the pipeconnection screwed off in the direction of arrow A in FIG. 1 and

FIG. 5 is a front view of the tap head similar to FIG. 4 in thedirection of arrow B in FIG. 2.

The tap head for keg fittings illustrated in the drawings comprises ahousing 1 with a pipe connection 2 for introducing pressure gas, e.g.,compressed air or CO₂, and a sliding guide means 3 arranged on theunderside of the housing 1 for enabling the housing 1 to be pushed inthe known manner onto the keg fittings of the barrel-like container, forexample, a beer or lemonade container, and attached to them so that thetap head and the keg fittings are connected in a secure and sealedmanner with one another.

An essentially hollow cylindrical slide 4 is displaceable in the housing1 parallel to the longitudinal axis of the housing 1. A pipe connection5 for the liquid to be tapped, for example, beer or lemonade, isarranged at the top of the slide 4. The slide 4 contains in its interiora loose, spherical valve body 6 which interacts with a valve seat (notillustrated) on the slide 4 and forms a check valve for the tappedliquid.

There is pivotally mounted on the housing 1 by means of a horizontalthrough bolt 9 an actuating lever 11 which has a relatively spaciousrecess 12 in the region of the housing 1 (cf. FIG. 3) with which itencircles the upper portion of the housing 1 such that it is pivotableback and forth between an upper position and a lower position. From theactuating lever 11 which is fork-shaped in the region of the recess 12,two pins 13, 14 project inwardly in the region of this recess 12 andengage in recesses 15 on both sides of the slide 4. As is apparent fromFIGS. 1 and 2, the recesses 15 have openings which widen for insertionof the pins 13, 14.

When the actuating lever 11 is pivoted between its two extremepositions, the slide 4 is moved--via the pins 13, 14--with it. The upperposition is the closed position of the tap head, the lower position theopen position of the tap head. In the closed position, the tap head canbe removed sideways from the keg fittings by means of the sliding guidemeans 3 or connected therewith. In the open position, the pipeconnections 2, 5 are connected in a manner known per se withcorresponding passages (not illustrated) in the keg fittings for gas andliquid, respectively.

There is integrally formed on the housing 1 which, in the illustratedembodiment, like the other parts of the tap head, consists of plastic, aspring tongue 18 (similarly made of plastic) which projects freelyupwards and has a detent nose 19 in its upper region. As illustrated,the upper end of the spring tongue 18 constantly engages in the recess12 of the actuating lever 11. When the actuating lever 11 is pivotedfrom its upper into its lower position (illustrated in FIGS. 1 and 2),the spring tongue 18 is elastically biased until its detent nose 19 isfinally located above the upper side of the actuating lever 11. Thisdetent nose 19 then protrudes over an associated detent edge 31 of therecess 12 (FIGS. 1, 2 and 3) and the actuating lever 11 is hereby lockedin this lower position.

An annular collar 21 provided at the bottom of the slide 4 with openings(not illustrated) for passage of the gas can rest against an annularstop edge 22 of the housing portion 1 when the tap head is in its closedposition. When the tap head is in its open position (FIGS. 1 and 2), aseal (not illustrated) provided at the bottom of the slide 4 serves toseal the slide 4 on the keg fittings in a manner known per se.

The sliding guide means 3 contains an annular seal 24 whosecross-sectional shape is apparent from FIGS. 1 and 2 and which likewiseacts as a seal relative to the keg fittings. As illustrated, there isformed on the sliding guide means 3 an inwardly extending annular collar20 which engages in an outwardly opening annular groove in the annularseal 24 and thereby serves as a support for this annular seal 24. Whenthe slide 4 is pressed downwards by the actuating lever 11, with the taphead in its open position (FIGS. 1 and 2), the outer rim of the annularcollar 21 provided on the slide 4 engages a conical inclined surfaceformed on the seal 24 and thereby presses this seal sealingly against aplate 30 of the keg fittings mounted on the barrel (FIG. 4).

The sliding guide means 3 can be in the form of a spring elastic plasticpart which is separate from the housing 1. The sliding guide means 3 issubsequently firmly connected to the housing 1 which, as a rule, willalso consist of plastic, by being, for example, screwed, welded oradhesively joined to it. In the illustrated embodiment, the slidingguide means 3 whose outline is essentially apparent from FIG. 3, isinserted into a recess in the housing 1 which corresponds to thisoutline.

As is apparent from the drawings, the sliding guide means 3 comprises aU-shaped guideway 32 for the plate 30 of the keg fittings. The guidewayis formed by an upper wall of the sliding guide means and an inwardlyprojecting guide piece 33 arranged at a distance below this wall. Thisgroove-shaped guideway 32 is open towards the left in FIG. 1 and closedtowards the right by the U-shaped bend to enable the tap head to bepushed from the right onto the plate 30 of the keg fittings. The guidepiece 33 then engages under the rim of the plate 30. When the tap headis pushed onto the plate 30, the actuating lever 11 is in its upperposition (not illustrated) and the tap head is, therefore, in its closedposition.

In FIGS. 1 and 4, the tap head is clamped in its normal operatingposition on the plate 30 of the keg fittings. The annular seal 24 isfirmly and sealingly pressed onto the surface of the plate 30 by theslide 4 which has been moved to its lower position so that liquid can betapped in the usual way from the container provided with the kegfittings.

When an inadmissibly high gas pressure builds up in the housing 1 of thetap head and hence also in the container (keg) carrying the keg fittingsvia the pipe connection 2, for example, when the connection 2 isconnected by a tube to a CO₂ bottle, with a pressure reducing valveinterposed between these, and this pressure reducing valve is faulty, asillustrated in FIGS. 2 and 5, the housing 1 lifts with the annular seal24 off the surface of the plate 30, thereby producing between annularseal 24 and plate 30 a gap 34 through which pressure gas can escape intothe environment and an excess gas pressure can be released. The gasflowing out into the environment is indicated by arrows in FIGS. 2 and3.

The resulting gap 34 can have a height of, for example, approximately 1to 2 millimeters. The width of the gap (cf. FIG. 3) can be, for example,approximately 60 millimeters. The gap 34 thus forms a sufficiently largeopening to allow a large amount of excess gas to escape rapidly and aninadmissible excess gas pressure to be reduced.

It has been found that owing to the large gap opening, foreign bodies,for example, ice, sugar residues or the like are blown away by theescaping gas. Clogging does, therefore, not occur. In contrast toseparate pressure relief valves, the arrangement according to theinvention wherein, if necessary, the entire tap head lifts off the kegfittings, therefore, operates in a self-cleaning and maintenance-freemanner.

The opening pressure at which the tap head is to lift off the kegfittings can be set by appropriate design of the spring elastic guidepiece 33 on which the rim of the plate 30 rests. It is possible to setthe modulus of elasticity of the material forming the sliding guidemeans, in particular, plastic, and the geometry and the dimensions ofthis guide piece 33 such that the tap head lifts off at a desired gaspressure, thereby forming the gap 34, and hence acts as pressure reliefvalve. Normally, liquids are tapped from containers provided with kegfittings at an operating pressure of approximately 3 bar. The maximumadmissible pressure in the tap head and in the container isapproximately 7 bar. The guide piece 33 responsible for the lifting-offof the tap head is, therefore, designed such that the tap head lifts offat a pressure which is greater than approximately 7 bar.

The cross-section of the opening of gap 34 depends on the prevailingpressure, i.e., the gap opening becomes larger when the pressure isgreater and vice-versa. This, again, is based on the elastic resilienceof the guide piece 33 which engages under the rim of the plate 30 andunder relaxed gas pressure conditions brings the sliding guide means 3with the seal 24 back to the surface of the plate 30 again.

As illustrated in FIGS. 1 and 4, it is expedient for the guide piece 33to be designed so as to extend upwards at an incline because it thenundergoes deformation easily in the downward direction into the positionillustrated in FIGS. 2 and 5 when an excess gas pressure occurs. Inprinciple, the guide piece 33 can extend horizontally or even downwardsunder normal conditions, i.e., in the absence of excess gas pressure.This makes no difference to the fundamental way in which the tap headoperates as "pressure relief valve".

In the illustrated embodiment, the tap head essentially consistsentirely of plastic, i.e., apart from the sliding guide means 3 whichconsists of spring elastic plastic, the housing 1, the slide 4, theactuating lever 11 and the spring tongue 18 (integrally formed on thehousing) are also made of plastic. In other embodiments of theinvention, however, these parts may also consist of other materials, forexample, metal, as long as the sliding guide means 3 with its guidepiece 33 is made of spring elastic material or at least this guide piece33 consists of spring elastic material so as to enable lifting-off ofthe tap head from the plate 30 of the keg fittings.

We claim:
 1. Tap head for keg fittings comprising a housing, an annularseal arranged in the housing for sealing relative to the keg fittings, aslide movable in the housing, an actuating lever pivotally mounted onthe housing and connected to the slide, releasable locking means for theactuating lever, connections for gas and liquid connectable via theslide with corresponding passages in the keg fittings, and a slidingguide means arranged on the underside of the housing and forming aguideway for pushing the tap head onto the protruding rim of a plate ofthe keg fittings which rests against the annular seal, at least thesliding guide means of the tap head consisting of spring elasticmaterial and a projecting guide piece of the guideway engaging under therim of the plate, characterized in that the modulus of elasticity of thematerial forming the sliding guide means (3) and the geometry and thedimensions of the guide piece (33) are determined such that at a certaingas pressure, the housing (1) of the tap head lifts off the plate (30)of the keg fittings, with the guide piece (33) thereby undergoingdeformation, and a gap (34) through which excess gas pressure isreleasable is thereby created between the plate (30) and the annularseal (24).
 2. Tap head as defined in claim 1, characterized in that thegap (34) increases as the excess gas pressure rises, and closes again asthe excess gas pressure drops.
 3. Tap head as defined in claim 1,characterized in that the guide piece (33) engaging under the rim of theplate (30) extends upwards at an incline.